1. Field of the Invention
The present invention relates to a data analysis device, a data analysis method, and a program for detecting a step on the ground based on point cloud data representing a three-dimensional shape of a feature on the Earth's surface.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2009-204615 discloses a technology for acquiring three-dimensional point cloud data representing a shape of a feature on the Earth's surface using a laser scanner. For example, in a mobile mapping system, a laser scanner is installed on a motor vehicle, and a laser is radiated obliquely downward from a top of the vehicle body. The direction of radiating the laser is swung widthwise, and a laser pulse is emitted for each small angle across a scan angle range. A distance is measured based on a period from the emission of the laser to reception of reflected light, and the direction of the emission of the laser, the time, the position and attitude of the vehicle body, and the like are measured at this time. Then, point cloud data representing three-dimensional coordinates of a point which reflects the laser pulse is acquired from the measured data.
Moreover, video is taken using a camera simultaneously with the acquisition of the point cloud data. The image can be used by a user to specify a part to be measured in a data analysis.